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authorRavi Bangoria <ravi.bangoria@linux.ibm.com>2019-11-08 15:11:28 +0530
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-11-12 08:32:27 -0300
commitccd26741f5e6bdf2c18ea38b32e6a347c5648a97 (patch)
tree667bdd77c2c924c5db140c6a4bc20a496e15c25a /tools/perf/Documentation
parent7b018e298752b9bcaf34eba8e1d3c08e3207dfd8 (diff)
perf tool: Provide an option to print perf_event_open args and return value
Perf record with verbose=2 already prints this information along with whole lot of other traces which requires lot of scrolling. Introduce an option to print only perf_event_open() arguments and return value. Sample o/p: $ perf --debug perf-event-open=1 record -- ls > /dev/null ------------------------------------------------------------ perf_event_attr: size 112 { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|PERIOD read_format ID disabled 1 inherit 1 exclude_kernel 1 mmap 1 comm 1 freq 1 enable_on_exec 1 task 1 precise_ip 3 sample_id_all 1 exclude_guest 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 ------------------------------------------------------------ sys_perf_event_open: pid 4308 cpu 0 group_fd -1 flags 0x8 = 4 sys_perf_event_open: pid 4308 cpu 1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 4308 cpu 2 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid 4308 cpu 3 group_fd -1 flags 0x8 = 8 sys_perf_event_open: pid 4308 cpu 4 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid 4308 cpu 5 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid 4308 cpu 6 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid 4308 cpu 7 group_fd -1 flags 0x8 = 12 ------------------------------------------------------------ perf_event_attr: type 1 size 112 config 0x9 watermark 1 sample_id_all 1 bpf_event 1 { wakeup_events, wakeup_watermark } 1 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.002 MB perf.data (9 samples) ] Committer notes: Just like the 'verbose' variable this new 'debug_peo_args' needs to be added to util/python.c, since we don't link the debug.o file in the python binding, which ended up making 'perf test python' fail with: # perf test -v python 18: 'import perf' in python : --- start --- test child forked, pid 19237 Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: /tmp/build/perf/python/perf.so: undefined symbol: debug_peo_args test child finished with -1 ---- end ---- 'import perf' in python: FAILED! # After adding that new variable to util/python.c: # perf test -v python 18: 'import perf' in python : --- start --- test child forked, pid 22364 test child finished with 0 ---- end ---- 'import perf' in python: Ok # Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lore.kernel.org/lkml/20191108094128.28769-1-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation')
-rw-r--r--tools/perf/Documentation/perf.txt2
1 files changed, 2 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt
index 401f0ed67439..3f37ded13f8c 100644
--- a/tools/perf/Documentation/perf.txt
+++ b/tools/perf/Documentation/perf.txt
@@ -24,6 +24,8 @@ OPTIONS
data-convert - data convert command debug messages
stderr - write debug output (option -v) to stderr
in browser mode
+ perf-event-open - Print perf_event_open() arguments and
+ return value
--buildid-dir::
Setup buildid cache directory. It has higher priority than